In a semiconductor production process, there is conducted a processing of supplying a treating liquid (chemical or deionized water) to a surface of a semiconductor wafer as a substrate to be processed (hereinafter simply referred to as a wafer). In particular, in a substrate cleaning device for cleaning a wafer, a chemical for a cleaning processing is supplied onto the wafer surface, and deionized water is then supplied thereonto to execute a rinsing processing. After subjected to the rinsing processing, the deionized water is being attached to the wafer surface. To remove the deionized water thus attached, the wafer is rotated at a high speed to conduct a drying processing in order to shake off the deionized water on the wafer surface.
A typical substrate drying device used for this drying processing has: a spin chuck to be rotated while horizontally holding a wafer; and a rotationally driving mechanism for rotating the spin chuck at a high speed. This arrangement achieves the substrate drying by shaking off the deionized water with the use of the centrifugal force acting on the deionized water with the rotation.    Cited Patent Document 1: Japanese Unexamined Patent Publication No. 10-41270